Burglar alarm box



Jan. 27, 1953 F. E. POULSON 2,627,065

BURGLAR ALARM BOX Filed Dec. 28, 1949 3 Sheets-Sheet 1 Z t INVENTOR. J67 Frank f. Poalson BY pzif my 6 days Jan. 27, 1953 F. E. POULSON 2,627,065

BURGLAR ALARM BOX Filed Dec. 28, 1949 3 Sheets-Sheet 2 30 5c; 55 20 l 2 54 If] ,7 1c

.25 .25 2/ 15 l t W 3 Wmoow, Do n E IN V EN TOR.

BY Frank if Poalsorz Jan. 27, 1953 F. E. POULSON 2,627,065

BURGLAR ALARM BOX Filed Dec. 28, 1949 3 Sheets-Sheet 5 \/\/|NDow D009. ETC. Swrrcmzs INVE'NTOR. Frank E P01125071 66 BY 7;) at" a Patented Jan. 27, 1953 UNITED STATES PATENT OFFICE BURGLAB. ALARM BOX Frank E. Poulson, Chicago, 11]., assignor to Certified Burglar Alarm Systems, Incorporated, Chipage, Ill.,"a corporation of Illinois Application December 28, 1949, Serial No. 135,413

(Cl. MIL-2'76) 9 Claims. 1

This invention relates to improvements in bur.- glar-alarm bell boxes such as are related to or used in connection with protective circuits of premises, whereby to sound an alarm if the building orthe alarm system or the box itself be tarnpered with in an effort to effect entrance to the premises.

Such boxes are ordinarily securely mounted with their bottom faces flatwise against the wall and most often up against the ceilingor special ceiling in the door entry of the store or premises to be protected.

The alarm bell itself includes preferably a large gong and operating magnet mounted in the interior of the box and is capable when operated of making a loud sound. The box being mounted outside the door, the sound carries still further. However, such exposed position makes the bell and box especially vulnerable to burglar attack. Accordingly, it is an object of this invention to provide a burglar-alarm box so constructed, arranged and installed that it is difiicult to prevent its alarm operation when subject ,to attack.

Another object of the invention is the provie sion of an alarm box in which the base member is insulated from the other parts thereof and from the protective circuit .or branches thereof which pass through the box, whereby the base member is not grounded or if grounded does not affect the operation of the alarm.

Another object of the invention is the provision of an alarm box havinga base member and a cover member fitting thereover, the edges ofthe cover member being closely related to the corner edges of the base member but slightly spaced therefrom when the cover is so fitted and secured in position, whereby in any attempt to pry the box loose from its mounting by a tool, thelatter is most apt to engage the edge .of the cover and to loosen the same and thereby to set the alarm bell into operation.

further object of the invention is the provision of a three-part alarm box comprising base and cover members and an inner suspended bellcarryin framemembe'r, the said threepartsbeing secured together but insulated from each other, the cover memberbeing connected to one side of the protective circuitwith which the box is related and the said framemernber being connectedto the other sideof said protective circuit, whereby any driling into or otherwise tampering with the box from the outside electrically connects the top and framemembers, short-circuits the relay and sets off the. alarm.

Further features, advantages and objectswill appear from the description and claims to follow, in connection with the accompanying drawings which illustrate, by way of example but not of limitation, a burglar-alarm box embodying the invention, and in which- Fig. 1 is a plan View of the improved burglar alarm bell box, part of the cover being broken away to show parts beneath;

Fig. 2 is a similar View with the cover and bell plate removed;

Fig. 3 is a sectional elevation of the box on the plane indicatedby the line '33 of Fig. 1;

Fig. 4 is a detail view of one of the alarm switches inthe box;

Figs. 5 and 6 are front and edge views of the switch of Fig. 4, but reversed in position;

Fig. 7 is a diagram of the circuits involved;

Fig. 8 is an exploded view of three main parts of the box, showing them in perspective; and

Fig. 9 is a simplified-diagram of the circuit.

As shown, the box comprises a shallow rectangular heavy sheet-metal bottom portion, generally indicated by It, a similar cover portion H adapted to be placed thereover with their edge portions in free, non touching, telescoping and insulated relation, and a cell it and bell-carrying frame l3 inside the box and insulatingly supported thereby. By thus insulating the'bellfrarne from the surrounding-box structure and thecover also, and suitably arranging the circuits and apparatus as will be explained, many of the efiorts and tricks of burglars to put the alarm bellout of commission are not only thwarted but result in operating the beil and soundingthe alarm if attempted.

The bottom portion iii of the box includes the bottom plate H! with its edges bent up to form the sides lfi. Sheetmetal corner pieces it may be bent, fitted and welded into the corners of the bottom boxmember it]. They extend above the sides it of the box and at their upper ends carry blocks ll of suitable electrical insulating material which may be bolted or secured by screws thereto, as indicated.

The cover H by its fiat top it and depending side edges is overlapped and welded together at the corners rests on their insulating blocks H and is secured thereto, as indicated,by-thescrews 28, one in each corner, in which position the cover of the vbox is electrically insulated-from thelower partliljthereof. Y

The bell carrying frame [3 comprises a sheetmetal strip -21 bent and 'suitably welded together to form a continuous frame of the formindicated in plan View inFig. 2, is, viithrectangular sides 22 and diagonal corners 23, each with an internal flange 24 at the upper edge.

This frame is carried by insulating supports 25 from the adjacent side edges I of the box base member and are also spaced thereby from the box, which supports may be in any desired number, but two along the sides and one at the ends, as indicated, have been found satisfactory. These insulators may be of any desired type. Bolts passing through shouldered insulating sleeves as spacers and insulators with insulating washers and nuts inside are sufiicient. This frame is thus supported above and out of contact with the bottom I4 of the box I0.

A bell plate 26 of a size to rest and fit on the flanges 24 of the insulated frame I3 is secured thereto around its periphery by suitable screws 21 or otherwise.

This plate on its under side carries the alarm bell gong I2 and its operating magnet 28, armature, striker 29, circuit breaker, etc.

In this arrangement, therefore, the bell and its frame and the cover are insulated from each other and from the box.

The box itself is adapted to be secured to a wall, ceiling or suitable support by four screws, bolts or the like inserted through holes 30, Fig. 2, in the bottom I4 thereof. It is frequently located in the entry to the store or premises, on the ceiling up over the door. The battery for operating the bell and control relay and the relay itself in a suitable switch box may be located inside the premises in some more protected position and are connected with the alarm box by wires in a suitable armored cable or conduit which may connect with the alarm box through aperture 3|, Fig. 2, in the bottom thereof. The wires themselves or some of them are connected to suitable terminal posts 32, 33, 34 and 35 which are insulatingly mounted on the inner face of one side 22 of the frame I3 and internally connected with other parts of the apparatus of the alarm box, as will be explained. Two other wires 80 of the cable enter the box and go directly to the bell. These permanent wires in the box are ordinary insulatingly covered wires and are indicated by dotted lines in Fig. 2 rather than confuse the drawings by attempting to show them in full. They are also indicated in the diagram of Fig. 7.

The external circuits and apparatus may be of the usual type and are here included to illustrate the operation of the alarm box.

The alarm switch shown in Figs. 4, 5 and 6 is shown used in three different locations in the alarm box, as will appear. In two of the locations the switch is suitably mounted on the inner face of the diagonal member I6, as seen in the lower left and upper right corners of the box It], Fig. 2, and beneath the insulating block H with its upwardly spring-pressed operating plunger 36 in line with the screw 20 which is used to secure the top or cover member II in place on the base member of the box. When, therefore, the cover is applied to the base member and the screws 20 are tightened, the plunger 36 of the switch, which latter may as a whole be designated 31, is depressed and the switch is operated to close the circuit it controls at that point. Whenever either of the two screws 20 is loosened, therefore, surrepititiously or otherwise, the plunger 36 rises under the influence of its springs to open the circuit and cause the alarm bell to operate.

The switch itself may be of any desired or usual construction, but as shown in Fig. 4 comprises the plunger 36 extending longitudinally through the casing and projecting therefrom at the lower end, the casing having the laterally projecting ears 38 by which it is secured by screws or otherwise to the base I6, a layer of insulation being provided thereunder. A suitable spring within the casing constantly urges the plunger upwardly or toward the open position. A sliding contact 36a, Fig. 6, insulatingly carried by the plunger 36 bridges the two contacts of the switch on the inside of the casing when the plunger is in its lowermost position and separates or disconnects them electrically when the plunger is raised. These two switch contacts are connected with or form a part of terminal posts on the exterior of the casing, which may be apertured for the reception of pins 46 on the ends of their respective conductors or wires. These terminal pins may be of the type known as banana pins or plugs, that is, with split ends normally spread apart slightly at their outer ends and tensioned outwardly so that the pins may be pressed through or into the apertures in the posts and the spring fingers will hold the plugs therein and in good electrical contact. Any other desired form of connection may, of course, be used.

Another of these switches 31 is placed upside down from the position of the other two on the inside face of one of the side members of the insulated frame I3, as indicated at the lower side of Fig. 2. It is insulatingly secured to and carried on a suitable raised bracket 41 from the floor I4 of the base box member ID, with the end of its plunger 36 projecting through an enlarged aperture in said floor under its spring pressure and below the bottom face of the floor or bottom I4 of the box I0, whereby when the box is mounted on its support the end of the plunger 36 strikes the said support and is pushed up against its spring tension, to close the circuit through its contacts. When, however, the box is pried or raised up from the support, the said plunger 36 is released and pushes outwardly and thereby opens its circuit through the contacts 45 and causes the sounding of the alarm.

The internal wiring of the alarm box, Figs. 2 and 3, is indicated by the broken lines which represent the insulated wires used singly or in twisted pairs and suitably secured in position within the box. Thus, the terminal post 32 is connected by conductor 50 with one terminal of switch 31 in the lower left corner of Fig. 2. The other terminal of that switch is connected by conductor 5I with the insulated bell frame I3 at the point 52. The binding post 33 is connected by wire 53 with a plug socket 54 insulatingly carried on the wall of the frame I3 above the level of the upper edge of box base member I0, as indicated in Fig. 3. This socket 54 is adapted to receive a banana plug, such as referred to above, on a conducting cord 55 which, as seen in Fig. 3, is attached mechanically and conductively to the cover member II at 56. The terminal post 34 is connected by wire 51 with the other corner switch 31 and thence by wire 58 with the upside-down switch 3! before referred to. A wire 59 connects this switch to a plug socket 60, like socket 54 before described. A flexible cord 6| having a banana plug may connect the socket 60 with the cover II at another convenient point, designated 62 in the diagram of Fig. 7 but not shown in Fig. 3. Binding post 35 is connected by conductor 63 directly with the frame I3 at a point designated 64, shown on the side wall thereof in Fig. 3.

The conductors in the conduit coming into the bottom of the alarm box through the aperture 3| are for the sake "of cleai'ness shown in Fig.2 as separated broken linesthose rrdmtne battery and from the relay being connected directly to the binding terminals or posts 32 to 35, as hereinafter explained, and the, bell conductors leading directly to the bell without beingco'nnected to such posts or terminals. 7

In the diagram of Fig. 7 the outlines of the cover I l and of the inner insulated frame I3 are shown in broken lines. Here the bell T2 is also shown and its operating magnet 28, which, as indicated, is of the make-and-b feak type. The current used in such apparatus is usually direct current from a set or sets of dry batteries and may be of about 6 volts potential. Accordingly, the bell in operation makesfan'd breaks, it's own circuit in the well-knownmanner. V

It will be noted that the base member 1 hr the box is not connected with the circuit, but that, both the insulated frame I3 inside and the insulate d cover member ll outside are "connected with the circuit; also, that as between the 'batitery and the relay the insulated cover is in one side of the circuit and the insulated fram'e in the other, so'that any attempt to drill through the two or to press or bend them so that they touch results in short' ci'rcuiting the relay "and causes it to close "the alarm bell circuit.

Referring to Fig. 7, a simplified diagram of external circuits and aparatus with which the alarm box may be used or related is indicated. These include a suitable battery or source '65 in the protective alarm circuit for operating the relay G5 which is normally energized and holds open the contacts 61 in the independent bell circuit, which includes a battery or source of current 68 as well as a normally closed switch 69, commonly referred to as a key switch because operable only by keys in the possessionofa-uthorized persons. 7

The relay 66- is of thatftype which when-once opened or de-energiied cannot meve its a'rma' hire to closed position uhtu it has been reset, manually or otherwise. Thus, the bell, once started, keeps ringinguntil purposely stopped. This operation of the-relay 66 is diagrammatically indicated by its armature closed contactsin its circuit, butother constructions may be used. As here diagrammatically shown, it would be necessary manually to move the armature to closed position to again set the reIa'y'GB in position to operate, but in practice it is foiind convenient to provide'th'e ke y switch 89 with contacts suitably 'conne'ctedto bridge thesaid a rmature contacts of the relayyorprovidean extra coil on the relay, so that in turning the key of switch 69 the relay B6 is operatedan'd thereafter maintains itself in operatedposition'through its said armature contacts.

Now tracingthe relay circuit from the battery 65, conductor l9 after passing first through its protective loop which passes through such places as windows, doors, etc, indicated by the numeral 11, leadsto theterminal post ;32--of the alarmbo'x, and thence by conductor'iil, closed switch 31 and conductor. 5! to theinner insulated frame I 3 at the point 52. From this frame at thepoint 64, diagonally. opposite, the path for current proceeds by way of conductor -83 and terminal post SSQWHereit leavesthe alram box by conductor 7| tothe'reIa'y 66. Onthe other side of the relay 66 the, return'path includes conductor 12 to theterminal l'post 54 "on the alarm box, and in the box'via wire 5'Ijclc'sed switch 31,

6 wire 58, upside-down switch 31, and conductors 59 and 6| to the cover I I, where it is attached at 62. The current path is then through the material of the cover to the point 56 at the opposite side, where the conductor 53 takes it to the bind ing post 33. From here the path proceedsby external conductor 13 through protective loop 15 to the other pole of battery 65. Thus the inside frame 13 in the box is in one-side or the circuit or connected with one pole of the battery, and the cover II is in the other side of the circuit or connected to the other poleor the battery. Any attempt to drill therethro ugh to short-circuit the battery on the relay to keep it energized and the bell quiet, so that the protective circuit elsewhere,

as at the loop referred to, might be broken with impunity wi'thout sounding the alarm, is prevented because any such 'sh'ort cirouitihg. would effectually cut out "the relay, short-circuit it, and cause the relay to de-energize and thus to operate the bell. Likewise, if the cover were bent or crushed inwardly so that it touched the inner frame, the relay would be short-circuite'd and operate the bell. And, of course, as pointed out, any attempt to remove the two screws of the cover or the vertical separation of'the box base from its support would result in the opening 'of the circuit of the relay at switch or switches 31 and the ringing of the bell.

In this connection itwill be noted that the base member I 0 of the alarm box isfirmly'secured to its support, the wall or ceiling, by bolts or the like, through the corner holes 30' in the :bottom thereof. The cover member II, however, is secured to the base member by the corner bolts 20 threading into the blocks l1 of insulating material, which is of softer material. therefore weaker to an outward 'pull'on the cover than the connection of the box base to its support, so that any effort made to pry the box loose from its support by working alo'ng'its edges or otherwise will cause the cover to give way first and thereby release the switch or switches" 31 to thereby open the protective'circuit and ring the bell. And in furtherance of this feature, the

slight outward spacing of the coveredge from. the base member and the termination of its extreme lower edge slightly above the bottom of the box member, as indicated in Fig. 3, tends to 1 cause any such prying effect on the box to be exerted against the top member rather than the base member and therefore the more certain to lift the cover from the base andthereby operate the switch or switches'31.

Likewise, if'the base member 'of'the box is pried loose or raised slightly from its support, the

switch 31 (Figs. 2, 5and 6)v in the: protective circuit opens the same and soundsithe alarm.

The circuit relation of the alarm box to the energized relay 66 in the other. clear that the cover H is in one side of the cir cuit and the inner. bell frame 13 is in the other side; also, that the base member w of the box is i not in the protective circuit at all, andthat any grounding of the base-member of the box would not aifect theoperation of the alarm box.

The protective loops |5'I6, Fig. '7, are, of course, such that severing either of the wi'r'es'or' both or short-circuiting them "results in the 'deenergization ofrela'y lifi and the 'o'perati'onof the 1 This latter connection is bell. The points marked 11 on the loop indicate the window, door or other contacts therein adapted to be opened to sound the alarm. While but a single loop 15-46 is indicated, it will be understood that the usual 12-hour and Z-hour service may be employed, such loops being usually controlled by a suitable key switch such as 69, whereby a portion of the protective loop may be cut out during the day and the remainder remain in operation, and at night both portions are cut in as one. This, however, need make no diiference in the connection or operation of the box itself.

Without further elaboration, the foregoing will so fully explain the gist of the invention that others may, by applying current knowledge, readily adapt the same for use under varying conditions of service, without eliminating certain features which may properly be said to constitute the essential items of novelty involved, which items are intended to be defined and secured by the following claims.

I claim:

1. In apparatus of the class described, a burglar-alarm bell box comprising a base member, a cover member and an inner member, all nested and secured together, said members being insulated from each other in the box, and an alarm bell in the box, a protective alarm circuit having a current source and a relay therein, the relay controlling said bell, the cover member of the box being connected to one side of the protective alarm circuit between the current source and the relay and the inner member being similarly connected with the other side of said circuit, the base member being insulated from both sides of the .said circuit, whereby any tampering with the box which results in electrically connecting the cover and inner frame members short circuits the relay and operates the bell, and any grounding of the base member does not affect the relay.

2. In apparatus of the class described, a burglar-alarm bell box comprising an underground box-like base member, an outer inverted box-like cover member fitting over said bottom member and insulatingly secured thereto, and an inner bell-carrying frame member insulatingly supported in said base member, a bell carried by said frame, a protective alarm circuit having a current source and a relay therein, the relay controlling said bell, said cover member being connected to one side of the protective alarm circuit between the current source and relay and the said inner frame similarly connected to the other side of said circuit, the ungrounded and insulated base member forming no part of the said alarm circuit, whereby any tampering with the box which results in electrically connecting the cover and inner frame members short circuits the relay and operates the bell, and any grounding of the base member does not affect the relay.

3. In apparatus of the class described, a flat burglar-alarm box comprising a bottom member and a cover member, an inner bell-carrying member enclosed Within the box, said members being secured together and insulated from each other, and the cover and the inner members being connected in the protective alarm circuit with which the box is related and between the battery and normally energized bell controlling relay usually provided in such circuit, and switches in the box in the said circuit holding the same in normal operative condition when the box is suitably mounted on its support and is closed but which are operated to cause the sounding of the alarm when the box is unwarrantly sought to be opened or loosened from its mounting.

4. In apparatus of the class described, a burglar-alarm box comprising a shallow metal base member, an inner metal frame fitting within the base member in spaced relation therefrom, insulating supports for said frame from said base member, a removable plate peripherally secured to said frame, an alarm bell and an operating magnet therefor mounted on the lower side of said plate, and an outer enclosing cover member for the box fitting over the base and frame members and in spaced relation thereto, said cover member being insulatingly secured to said base member.

5. In apparatus of the class described, a flat burglar-alarm box comprising a, bottom member and a cover member, an inner bell-carrying member enclosed within the box, said members being secured together insulated from each other and the cover and the inner member being connected in the protective alarm circuit with which the box is related, fastening screws to secure the cover member to the base member, a switch in said circuit operated to maintain the said circuit in normal condition by one of said screws when inserted to fastening position, whereby on release of said screw the said switch is operated to cause the sounding of the alarm.

6. In apparatus of the class described, a flat burglar-alarm box comprising a bottom member and a cover member, an inner bell-carrying member enclosed within the box, said members bein secured together insulated from each other and the cover and the inner member being connected in the protective alarm circuit with which the box is related, a switch in the base member having its operative plunger projecting through an aperture in the bottom thereof and normally closing said circuit when the box is secured to a support and the plunger is pushed thereby to its circuit-closing position, whereby if the box is removed or pried loose from the support the said switch is operated and the alarm sounded.

'7. In apparatus of the class described, a burglar-alarm box comprising a base member having upstanding edge walls and a cover member with downwardly extending edge walls enclosing the base member, an alarm bell within the box and protected thereby, the edge walls of the cover extending outside and substantially spaced from the overlapped edge of the base member and in position to be first engageable by a prying tool in anattempt to pry the box loose from its mounting and a switch in the box operated by the raising of the cover from the base member to operate the alarm.

8. In apparatus of the class described, a burglar-alarm box comprising a base member and a cover member enclosing the base member, an alarm bell within the box and protected thereby, the c-overbeing secured to the base member and the base member being secured to a support, the cover-securing means being weaker than the base-securing means, whereby an attempt to pry the box loose from its mountings is apt to result in loosening and raising the cover from the box, switch means in the box responsive to such raismg of the cover to operate said alarm hell.

9. In apparatus of the class described, a burglar-alarm box comprising a base member and a cover member enclosing the base member, an alarm bell within the box and protected thereby, the cover being slightly larger than the base 10 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Miranda Oct. 11, 1932 Chapman et a1 Apr. 6, 1933 Mason July 17, 1934 Howton May 22, 1941 Fruh July 11, 1944 

